gebo

We went on vacation for a week and left our 2000 GS300 sitting in the garage. Got back yesterday and drove it to the grocery store and only got "warm" air with the AC on? Where would you start your diagnosis if you are gonna attempt to be a DIY'r? I have freon and know how to add.

The reason I'm asking the question is because it appears to have gone from cold AC to no AC just while sitting and not running for a week. It didn't slowly get warmer....

BDSL

Can be a few things...
Is the AC clutch engaging when you press the AC button?
If yes, is the pressure within spec? You will need the AC recharge kit to find out the pressure.

Bartman619

Some times when a compressor is low on refrigerant or compressor oil it will not run to prevent damage. Best thing to do is have the system checked out for leaks.

UDel

Once you make sure the fans are spinning when the AC is on and the compressor is working I would just try one of those AC canisters/kits before you take it to a dealership which will probably be a hefty bill. I lost most of my AC on 2 cars on hot days and tried those kits and they worked saving me money. You may have been so low on refrigerant that within a week enough leaked out it was enough to stop the AC from working at all so there was a night and day difference, that is what seemed to happen to me those 2 times.

gebo

Compressor was running

Hooked up manifold gauges and got this reading with engine idling and AC running for 15 minutes:
115 PSI Low pressure side
150 PSI High pressure side